Assembled type fixed electrode capacitive pressure sensor

Abstract

An assembled type fixed electrode capacitive pressure sensor can help solve problems of large quantities of fittings, easy attachment of gas in the ceramic insulating body, affected vacuum degree, large non-linearity, mismatch of a movable electrode shape change and a fixed electrode surface shape, and the like in a conventional capacitive pressure sensor. A fixed-electrode insulator made of a sapphire single-crystal is fixedly supported at a center position of a cavity of a clamping and pressing ring with a cover via an elastic positioning device, a thin film movable electrode made of constant elastic metal is pressed between an annular plane on a bottom part of the fixed-electrode insulator and an annular plane with an pressure guiding opening in a supported manner, and both faces of thethin film movable electrode are coated with precious metal layers; the film movable electrode of which the both faces are coated with precious metal layers is in close contact with the fixed-electrode insulator under pressure applied via a triple wave gold plated pressure spring. The sensor disclosed in the invention is simple in structure, reasonable in design, easy in manufacture, high in production efficiency and reliable in use; zeroing is not needed for a long time, an air inflow and an air outflow are reduced, leak rates are greatly lowered, a vacuum degree can be kept for a long time,and measurement stability and measurement precision can be improved markedly.

Description

technical field [0001] The invention relates to a capacitive pressure sensor for measuring a gas medium, in particular to an assembled fixed electrode capacitive pressure sensor in which a fixed electrode and a dependent movable electrode are crimped and packaged together. It is suitable for measuring the small pressure of gas medium, small absolute pressure (vacuum gauge). Background technique [0002] At present, capacitive pressure sensors based on the principle of parallel plate capacitance have an absolute advantage in measuring the small pressure of gaseous media, small absolute pressure (vacuum gauge), especially for measuring corrosive media. The US MKS company is the main monopoly of such products and restricts sales to China. MKS's products use an assembled fixed electrode structure, such as Figure 4~5 As shown, it includes a film moving electrode 14, a fixed electrode 95, a ceramic insulator 15, a support 16 with a pressure port, an upper clamping ring 17 of the...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a capacitive pressure sensor with an assembled fixed electrode, which solves the problem that the existing capacitive pressure sensor has many accessories, the gas in the ceramic insulator is easy to adhere, affects the vacuum degree, has large nonlinearity, and the deformation of the moving electrode is closely related to the surface of the fixed electrode. Shape mismatch and other problems, its structure is simple, reasonable in design, easy to manufacture, high in production efficiency, reliable in use, no need to adjust the zero point for a long time, reduces the amount of air suction and air release, greatly reduces the leakage rate, and the vacuum degree can be maintained for a long time , significantly improve the measurement stability and measurement accuracy

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